The Basic Principle of Microbiology

Transcription

1 The Basic Principle of Microbiology

2 Chapter 1 The Basic Character of Bacterium

3 Section 1 Bacterial Morphology

4 I. Size of bacteria Measure unit μm (micrometer)

5 大 中 小 炭疽芽胞杆菌 3-10 μm 大肠埃希菌 2-3 μm 布鲁菌 μm

6 II Shape of bacteria Coccus diplococcus ; streptococcus; staphylococcus; tetrads;sarcina Bacillus streptobacillus; coccobacillus; mycobacterium; bifidobacterium Spiral bacterium vibrio ; spirillum ; helicobacterium ;

7 葡萄球菌

8 大肠杆菌 核梭杆菌 双歧杆菌 炭疽杆菌

9 炭疽杆菌 大肠杆菌 结核杆菌

10 幽门螺杆菌霍乱弧菌

11 Section 2 Bacterial structure

12 Structure of bacteria Plasmid

13 cell wall Elementary structure cell membrane cytoplasm nucleoid capsule Special structure flagellum (flagella) pilus (pili) spore

14 Elementary structure

15 Cell Wall

16 1. structure & chemical composition peptidoglycan(mucopeptide) 1) polysaccharide backbone N-acetylglucosamine (G) and N-acetylmuramic acid (M) linked alternately in a chain. 2) tetrapeptide side chain G + : ala-glu-lys-ala link muramic acid, G - : diaminopimelic acid (DAP) 3) pentapeptide bridge G + L-glycine 5

17 Structure of peptidoglycan of G + B. lysozyme M G M G G M M penicillin M M M G G M M G

18 Structure of peptidoglycan of G - B. G G G M ala glu ala DAP ala DAP glu ala M G

19 Special components of G + cell wall 1. teichoic acids: wall teichoic acid membrane teichoic acid (lipoteichoic acid, LTA) function : 1)provide the cell with its consistency 2)adhere------pathogenicity 3)antigenicity 2. protein: SPA, M-protein

20 Gram Positive Cell Envelope Lipoteichoic acid Peptidoglycan-teichoic acid r r r r r r r r r r Cytoplasmic membrane Cytoplasm

21 Special components of G - cell wall 1.lipopolysaccharide(LPS) 1)lipid A ---endotoxin, non-genus specific 2)core polysaccharide 3)specific polysaccharide O Ag 2.Outer membrane protein : exchange ; receptor (sex pili,phage); porin 3.Lipoprotein 4.periplasmic space

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24 2.function 1) protection 2) keep the constant shape 3) antigenicity 4) exchange material

25 Bacteria L-Forms cell wall deficient form 1)Morphology: cell wall deficient form fried egg colony 2)Media : high osmotic ; reversion 3)Pathogenicity G protoplasts G spheroplasts

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28 cell membrane mesosome mesosome invagination vesicular membrane increase membrane area septal mesosome : cell division mesosome mesosome

29 cytoplasm ribosome 70S (30S+50S) RNA(66%), protein(34%) rrna---23s, 16S, 5S antibiotic protein synthesize

30 ribosome

31 . plasmid extra-chromosomal genetic material circle double chains DNA replicated independently carry genetic information control some functions of bacteria factor F control sex pilus factor R control drug resistance col faction control E.col. to produce bacteriocin

32 plasmid

33 Special Structure

34 capsule slime layer outside the cell wall composed of polysaccharide or polypeptide pneumococcus >0.2 μm capsule <0.2 μm microcapsule

35 肺炎双球菌荚膜 荚膜

36 Function 1. anti phagocytosis 2. protect the cell wall 2. anti-dry 3. antigenicity 4. type

37 Flagella Long filamentous appendage Originate in the protoplasmic membrane Function 1. motility 2. antigenicity : H Ag 3. pathogenicity some bacteria (vibrio)

38 polar Peritrichous

39 pilus 1. common pilus : /cell adhere to suface of B. associated with pathogenicity. 2. sex pilus : 1-4/cell male bacteria with sex pilus transfer of genetic material(dna) during bacteria conjugation F F -

40 大肠杆菌 普通菌毛 大肠杆菌 性菌毛 普通菌毛

41 普通菌毛

42 spore dormant form (resting forms ) 1) forming: inadequate nutrition 2) germination spore vegetative form activation initiation outgrowth

43 肉毒杆菌芽孢 炭疽杆菌芽孢 肉毒杆菌芽孢 破伤风杆菌芽孢

44 破伤风杆菌芽孢 肉毒杆菌芽孢

45 core Structure of spore

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47 3) function highly resistant to heat, chemical and dry reason: (1)many layers ----thick coat (2)little water 40% free water (3)large amount of calcium dipicolinic acid (4)heat-stable enzyme ( 吡啶二羧酸钙 )

48 Section 4 Bacterial growth and reproduction

49 Bacterial requirements for growth nutrients optimal ph optimal temperature oxygen (or absence) osmotic pressure

50 Nutrient Requirements carbon inorganic salt nitrogen water growth factor

51 ph grow best at neutral ph: 7.2~7.6 Some can survive/grow - acid ph 3 - alkali ph 9

52 Growth temperature psychrophile: -5~30 mesophile: 10~45 human body temperature: 37 * pathogens * opportunists thermophile: 25~95

53 Growth atmosphere strict (obligate) aerobe strict (obligate) anaerobe facultative anaerobe microaerophilic bacterium

54 Reason that obligate anaerobes can t grow in oxygen condition: (1) Lack of cytochrome and cytochromase Eh 300mv/120mv (2) Lack of superoxide dismutase (SOD), catalase, peroxidase superoxide dismutase O 2- +2H + H 2 O 2 catalase H 2 O 2 H 2 O H 2 O 2 peroxidase H 2 O

55 osmotic pressure 0.5% Nacl halophilic bacterium: 3% Nacl bacterial L-form: 3% -5% Nacl

56 Mode and speed of Bacterial reproduction binary fission generation time: time for bacterial mass to double time for bacterial mass to double 20~30min

57 Growth in a broth culture ---The Growth curve (1) lag phase : adaptation (2) logarithmic phase: most rapid reproduction (3) stationary phase: rate of reproduction=rate of dead (4) decline phase: rate of dead > rate of reproduction.

58 decline

59 Growth in a solid medium---colony

60 Section 5 Bacterial Metabolism

61 Bacterial enzyme Exoenzyme Endoenzyme hydrolase coagulase metabolic enzyme respiratory enzyme

62 Metabolic products 1. Catabolic products and biochemical reaction VP test methyl red test citrate utilization test indole test

63 2. Anabolic products and clinical significance 1) pyrogen polysaccharide of G - cell wall(lps) anti-high temperature 121, 30min Fluid infusion reaction 2) toxin and invasive enzymes exotoxin endotoxin enzyme

64 3) pigment water-soluble P. aerogenosa ---green fat -soluble S. aureus golden 4) antibiotics killing or inhibiting substances produced by some kinds of microorganisms Actinomycete 5) bacteriocin protein by certain bacteria, which can kill or inhibit the growth of related strains. 6) vitamin